Archived fuel level = power loss/gain?

[Goddard]

sounds stupid but... ... ... . on the way back from bristol this weekend, pulling 5ver i thought the truck was running ok but did not remember having to drop to third gear more than once or twice the last time through that area. low on fuel i stopped and filled up. the truck seemed to have better power and pulled a little stronger. this makes no cents! could i have a lift pump dying? has anyone else heard of this? thanks for any help.

 

[Extreme1]

It it were older and had more miles I'd suggest a line chaffed through inside the tank. In your case I think it might be an air leak on the suction side of the lift pump letting air in. With a full tank, it doesn't have to pull as hard to get fuel so it would work better.



It could also be a blocked/stuck vent. There was some info on that previously on the newer trucks, try a search.

 

[Bob Cochran]

Could it be a better load of fuel?

 

[Goddard]

don't think so on the fuel. bought fuel in the same area on the way down. also it was in coal country, those guys will not put up with having bad fuel pumping into their trucks. i think this would be a good day to get on the phone and order some gauges!